Approximately 300,000 Americans sustain a Mild Traumatic Brain Injury (MTBI) each year. Although the injury is classified as mild, the brain is indeed injured. MTBI results in subtle neuro-anatomical and neuro- psychological deficits that may lead to disrupted lifestyle. Memory deficits, including recognition and temporal order abilities, have been reported after MTBI. We know little about the characteristics and trajectory of impaired recognition memory after MTBI. The aim of this application is to use an animal model to systematically explore recognition memory following MTBI. The intent is to characterize behaviors and examine brain tissue histologically. Such work is not yet possible in human. The exploration of the brain regions associated with recognition and temporal order memory deficits after MTBI, such as the hippocampus, the parahippocampus and the perirhinal cortex, will help determine some of the possible conditions under which behaviors resulting from recognition deficits are observed. Better understanding of recognition memory deficits after MTBI and the conditions under which they are observed will guide the development of targeted nursing therapies. [unreadable] [unreadable] [unreadable]